This invention relates to a method and apparatus for packaging a semiconductor die.
Burn-in testing is used to force infant mortality and cause latently defective chips to fail early in the manufacturing process. By forcing chip failure, the chip manufacturer can avoid unnecessary expenditure of time and money on latently defective or "bad" chips. Another valuable aspect of burn-in testing is that it provides an ongoing evaluation of the fabrication process. The burn-in testing can be static or dynamic. Static testing typically supplies power and ground to a chip which is cycled through different temperature ranges. In dynamic burn-in testing, test signals are also applied to the chips to exercise specific chip functions.
The burn-in testing requires electrical connections to the circuit. Electrical connections to the chip for burn-in testing can be made with probe cards or with wire bond connections. Probe cards use a large number of thin electrical probes which must make electrical contact with each input pad on the chip to supply the excitation signal to the particular circuitry associated with that pad. The probe card contacts can damage the input pads.
Alternately, wire bond connections can be used. Dies can be packaged, burn-in tested, and then removed from the package. The electrical connections used for burn-in testing can sometimes damage a contact area or wire bond pad of the die. In some cases, this damage can prevent a tested die from being re-packaged and/or used.
It is therefore advantageous to have a packaging method and apparatus which avoids the problem of damage to the contact area.